1. Field of the Invention
The present invention relates to a fin-shaped antenna apparatus for vehicle radio application, and more particularly to fin-shaped antenna apparatus with enhanced AM/FM radio reception and arranged on vehicle top casing.
2. Description of the Prior Art
The rapid progress of wireless technology provides more portability to electronic products. More particularly, the wireless electronic products generally comprise antenna designed for particular frequency, directive and radio strength. The conventional antenna is made into rod shape with length corresponding to the quarter wavelength of the radio wave used. Taking the antenna used for vehicle radio as example, the vehicle antenna is a telescopic rod for both AM and FM reception. However, the vehicle antenna might have the problem of retraction after long time use, which is troublesome for user.
To solve this problem, a helix antenna made of spiral metal wire is developed. However, the reception quality of the helix antenna is not satisfactory. Moreover, a glass antenna is developed wherein flexible conductive material is coated on vehicle glass to function as AM-FM dual antenna. However, the flexible conductive material is expensive. Moreover, a printed circuit board with special-shaped planar antenna is also developed. However, the signal reception quality is poor when the planar antenna is assembled to metal vehicle casing due to the signal absorption by metal casing.